1. Field of the Invention
The present invention relates to a power conversion apparatus including switching elements and transformers for generating voltages used to drive the switching elements.
2. Description of Related Art
As such a power conversion apparatus, there is described an inverter apparatus in Japanese Patent Application Laid-Open No. 2008-118815. This inverter apparatus includes upper arm semiconductor modules, lower arm semiconductor modules, upper arm drivers, lower arm drivers and a transformer. Each of the upper and lower arm semiconductor modules is a switching element constituted of an IGBT and a diode. The upper arm semiconductor modules are mounted in a row on the bottom surface of a wiring board. The lower arm semiconductor modules are mounted in a row on the bottom surface of the wiring board side by side with the row of the upper arm semiconductor modules. Each of the upper arm semiconductor modules is connected in series with a corresponding one of the lower arm semiconductor modules. The series connections each constituted of one of the upper arm semiconductor modules and a corresponding one of the lower arm semiconductor modules are connected in parallel with another.
The upper arm drivers are circuits to respectively drive the upper arm semiconductor modules. The lower arm drivers are circuits to respectively drive the lower arm semiconductor modules. The upper arm drivers are mounted on the top surface of the wiring board so as to be located above the upper arm semiconductor modules. The lower arm drivers are mounted on the top surface of the wiring board so as to be located above the lower arm semiconductor modules. The upper arm drivers are connected to the upper arm semiconductor modules. The lower arm drives are connected to the lower anti semiconductor modules.
The transformer is for supplying a voltage to drive the upper arm semiconductor modules respectively to the upper arm drivers, and supplying a voltage to drive the lower arm semiconductor modules commonly to the lower arm drivers. The transformer is mounted on the top surface of the wiring board so as to be located between the row of the upper semiconductor modules and the row of the lower semiconductor modules. The transformer is connected respectively to the upper arm drivers and the lower arm drivers.
The above inverter apparatus converts DC power inputted thereto to AC power. When the semiconductor modules perform switching operation, switching noise is generated. Also at this time, the semiconductor modules emit heat.
As described in the foregoing, the transformer is located between the row of the upper arm semiconductor modules and the row of the lower arm semiconductor modules. Accordingly, the above inverter apparatus has a problem in that the transformer is susceptible to the switching noise and the heat emitted from the semiconductor modules.